* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

html {
    font-family: Helvetica, sans-serif;
    font-size: 16px;
}

body {
    background-color: #eee;
}

a {
    text-decoration: none;
}

ol {
    list-style: none;
}

h1 {
    font-size: 2.6rem;
    line-height: 1.5;
    font-weight: 300;
    text-shadow: 2px 2px 3px #333;
    text-transform: uppercase;
}

header, footer {
    padding: 10px 50px;
    background-color: #52a6e7;

    font-size: 3rem;
    line-height: 1.6;
    color: white;
    
    position: relative;
}

header>span {
    text-shadow: 2px 2px 3px #333;
    transition: all 0.6s ease-in-out;
}

header>span:hover {
    color: #54b0f7;
    text-shadow: 20px 16px 3px #333;
}

header>a {
    display: block;

    position: absolute;
    top: 50%;
    right: 50px;
    transform: translateY(-50%);
    
    color: #fff;
    font-size: 1.4rem;
}

header>a:hover {
    text-decoration: underline;
}

section {
    padding-top: 10px;
    padding-bottom: 30px;
}

section>.inner-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

section>.inner-wrapper>ol {
    width: 80%;
    padding: 2rem;
    border-radius: 10px;
    background-color: #fff;
    box-shadow: 0 0 1px 1px #bbb;

    display: flex;
    flex-wrap: wrap;
}

section>.inner-wrapper>ol>li {
    width: 25%;
    border-radius: 10px;
    
    text-align: center;

    transition: all 0.5s ease-in-out;
}

section>.inner-wrapper>ol>li>a {
    padding: 1.25rem;

    display: block;
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;

    color: #000;

    transition: all 0.4s ease-in-out;
}

section>.inner-wrapper>ol>li:hover {
    background-color: #52a6e7;
}

section>.inner-wrapper>ol>li:hover>a {
    color: #fff;
}

footer {
    font-size: 1.2rem;
    line-height: 4;
    text-align: center;
}

section.nav-kbd>.inner-wrapper>ol>li,
section.popover-demo>.inner-wrapper>ol>li,
section.animation-resume>.inner-wrapper>ol>li {
    width: 100%;
}

section.canvas-demo>.inner-wrapper>ol>li,
section.visual-dom-event-model>.inner-wrapper>ol>li {
    width: 50%;
}

@media screen and (max-width: 320px) {
    header, h1 {
        font-size: 2rem;
    }
}

@media screen and (max-width: 980px) {
    section>.inner-wrapper>ol>li {
        width: 100% !important;
    }
}